How to make a stove with wood and coal
How to choose a factory and make it yourself?
Among various types of fuel, coal is the second most efficient. It yields only to natural gas. However, firewood is still the most popular. This they owe their accessibility.
But what if we combine these 2 types of fuel? On the one hand, this allows a more rational distribution of resources. On the other, it gives great flexibility. You can use the type of fuel that is at hand at the moment.
The principle of operation of wood and coal stoves
Technology does not stand still. And gradually a new trend is gaining popularity. These are the so-called long-burning furnaces. This design increases the burning time of laying firewood by 2, and coal – by 3 times.
The principle of operation of such a furnace is based on forced air supply and fuel combustion in the upper chamber. Fuel is pressed down with a special load, which drops lower as it burns. Air is blown by a fan.
This principle is fundamentally different from the classic, when combustion occurs due to the supply of air from below, through the blower.
Any solid fuel can be used in the furnace: brown coal, anthracite, briquettes, sawdust, firewood, etc. The fuel supply process can be automated. In this mode, the oven is able to work up to several weeks. As in the classic version, an ash chamber is located below. A grate is separating it from the combustion chamber.
Advantages and disadvantages
This solution has obvious advantages:
- the oven can work offline for up to 10 days;
- operating time on one tab of fuel for firewood is increased 2 times, and for coal – 3 times;
- low fuel quality requirements;
- simplicity of design and installation;
- the ability to add additional options.
But practice has shown that there are also disadvantages:
- you cannot add fuel until the previous bookmark is completely burned;
- need a dry place to store fuel;
- coal forms a lot of dust and soot;
- high fire hazard, if you do not comply with the requirements of SNiP 2.04.05-91;
- the ash pan should be cleaned after each furnace, and the chimney before each heating season;
- environmental pollution.
The furnace can be made independently or purchased factory analogue. The purchase option is preferable. Such a furnace will automate the process as much as possible. But it is not cheap.
In order to save, such a design can be made independently. It will not be equipped with modern automation, but this is often not necessary for a summer residence.
The best material for the furnace is heat-resistant alloy steel. Sometimes, with self-production, old gas cylinders are used. They are made of steel grade St3 with a high carbon content. Refractory bricks are also widely used.
A long burning stove on coal and wood can heat one room, or maybe a whole cottage. It all depends on the power. In the latter case, the furnace is used to heat the coolant – water, which enters the heating system.
Which oven is best to choose for a home?
Criterias of choice
When choosing a particular furnace, pay attention to the following characteristics:
- operating time on one tab of fuel
- coefficient of performance (COP).
The main criterion is power. It should be enough to heat the required area. Typically, the required power is taken at the rate of 1 kW per 10 m2 of area. But it is necessary to take into account possible heat losses.
- The worse the room is insulated, the more heat will go out. Accordingly, in order to save money, it makes sense to take care of reliable thermal insulation in advance.
- When buying a factory model, all data will be indicated in the product passport. If you decide to make the oven with your own hands, then you will have to do the calculation yourself. Divide the area to be heated by 10 and take 20% in reserve. So you get the power you need.
- The next parameter is the operating time on one fuel tab. Modern models can work autonomously up to 48 hours. The longer the operating time on one tab, the more efficiently the fuel is used. And the less often you need to add it.
- There are models that use a hopper to automatically add fuel. Such a furnace can work autonomously up to 10 days.
- The operating time of the furnace for giving on wood and coal on one tab should be at least 12 hours. You are unlikely to enjoy waking up at night to add fuel. Efficiency of factory models, it is 75-90%. Homemade analogues have 75-80%. Factory boilers are beyond competition. The only negative is their cost.
Review of the best models
The following table summarizes the 10 most popular solid fuel boiler models. This is a long-burning wood-coal stove for wood, coal, pellets.
If the furnace is not heated properly, up to 70% of heat can be lost. Below are the basic rules that must be followed.
Proper preparation of materials
Firewood is stored in a barn – a drovnik. Moreover, they should dry in the air for at least 2 years. Only then can optimum heat transfer be obtained from them. Year-old firewood will give 20% less heat. And half-year – 50% less.
But that is not all. In air, the moisture content of firewood is 25-30%. The optimal value is no more than 12%. Therefore, before the furnace they are dried in the room. If you place the firewood 1–1.5 m in front of the stove, then they will dry out in 48 hours.
To do this, use a special tub, in which the logs are folded (see Fig. No. 1 below). Such firewood will have the optimum humidity and give off the heat indicated in the directories. Firewood should not be kept closer than 1 m from the front surface of the stove according to fire safety rules. The design of the stove may include a special place for drying firewood – a woodcutter.
Furnace cleaning, ash pan and furnace inspection
It is necessary to clean the furnace from ash before the furnace. This will eliminate the possibility of fire due to not extinguished sparks. First, the furnace is completely cleaned of ash. All the remains are swept away in an ash pan. Then it is cleaned with a scoop. Ash should not be thrown away. This is an excellent mineral fertilizer.
Do not want to lose up to 40% of the heat? It is worth paying attention to the condition of the furnace. A loose fitting door can reduce the temperature in the furnace by 200 – 250 0 C. Which will reduce the power of the furnace by 20%. This will cause increased soot formation. And the power will decrease by another 15 – 20%.
It is necessary to wipe the doors, view and gate. Dust is the most common cause of fire in a chimney. Burning, it turns into bitumen. And forms a dense soot, which is very difficult to remove.
Another important step is traction testing.
If the draft is insufficient, all the smoke will enter the room and it will be difficult to bring the furnace to operating mode.
How to check traction? Very simple. Take a candle. Close the furnace door tightly. Blowing up – open. And they bring a burning candle to it. The flame should lean towards the furnace and burn evenly.
What to do if there is no traction? This means that either a steam plug has formed in the furnace or an air plug in the chimney.
It is necessary to fully open the blower, view and gate. And prepare kindling from newspapers, oiled rags or sawdust. The kindling is slowly burned in the furnace until the smoke breaks through the cork.
If all else fails, inspect the deflector. It may be damaged or clogged.
Filling and kindling the furnace
For the furnace, tongs will be a must-have tool. Without them, it will be difficult to fix burning logs or coal. And if the wood, burning, settles unevenly, then a lot of heat is wasted.
How to fill the oven correctly? First, in the middle of a future bookmark, kindling is laid. It is best to use an oiled rag. Only it should not drip. Also use a few sheets of newspaper or thin dry slivers.
Classic is option number 1 . Firewood is laid in the same way as in a woodpile. Option No. 2 is used if the firewood is too large or not dry enough. In the middle it should be free, and the gaps between the logs make 2-3 times less than their width. And method number 3 is suitable in the case of a small firebox.
The main rule: firewood is laid so that to the top of the furnace there are 15 – 20 cm.
After the furnace has been kindled, the gate is half shut. The furnace door is tightly closed, and the blower door is ajar for 2 to 3 fingers. After 10 – 15 minutes, the oven itself will go into operation.
The furnace body begins to heat up and a uniform rustling is heard. If there is no noise, then you need to add air. To do this, check whether the firewood is burning and open the blower. After 5 minutes, check again. No rustling again? Slightly open the gate. If it doesn’t help, the blower is fully opened.
It happens that the stove does not rustle, but buzzes. In this case, there is too much air. Slowly cover the gate. Wait 2 to 3 minutes. Repeat the procedure. And so on until the rustling.
Before you add firewood, pay attention to the color of the flame and coals. White color indicates an excess of pyrolysis gases and oxygen. If yellow, the temperature is optimal and the fuel is used efficiently. Red – fuel does not burn out completely. Too weak or lack of oxygen. Orange – heat is consumed for graphitization and soot formation. Blue – the emission and combustion of carbon monoxide.
Accordingly, it is necessary that the color of the flame is yellow. If there is little air – gradually open the blower. If there is too much oxygen, they cover the gate.
Another trick with the furnace – you can not open the door of the furnace for more than 20 seconds. Otherwise, the heat loss will be too large. And the stove will go astray.
If you need to lay firewood and it did not work out during this time, then you can re-open the door only after 3 minutes.
Firewood should be reported in the oven in rows. You can immediately add up the remainder. But between the wood and the top of the furnace should remain 15 – 20 cm.
Fuel is added only when the ends of the logs are completely charred. The first log is laid obliquely. And the rest of the firewood is already stacked on top. So the furnace is as if divided into 2 zones. Below, the first batch burns out, and above firewood light up almost instantly. Therefore, heat loss is minimal.
After 5 to 10 minutes, they again check how the oven works. If necessary, bring it to operating mode.
At this stage, it is important to prevent carbon monoxide from entering the room. And do not release heat into the pipe. The last item is especially relevant for a brick oven.
It is very easy to determine the formation of carbon monoxide. This is evidenced by the blue tongues of flame or a coating on the coals of the same color.
In this case, the coals must be evenly distributed over the entire surface of the furnace. Next, close the gate and open the blower. The gate has a hole. Therefore, minimal traction will still be present. If the firewood is of good quality, then the coals will burn for 10 minutes.
If the coals become red, then there is no point in waiting until they completely burn out. This indicates the poor quality of the fuel itself. Therefore, they simply dig out all the coals and extinguish in a bucket of water. They could smolder for several more hours, practically without giving heat. Meanwhile, the heat would go out.
After all the fire has been eliminated, close all the dampers and doors as tightly as possible.
Coal is stored in a separate dry room. At room temperature. The room should be tightly closed. Otherwise, the formation of dust and soot throughout the house cannot be avoided.
The main difficulty with coal firing is that it requires a significantly higher temperature for ignition. About 800 – 900 0 C. Therefore, coal is more difficult to set on fire. To do this, use special lighters that give a flame with a temperature of 1000 – 1100 0 C.
In factory models are such devices. But the same effect can be achieved using a normal oiled rag. Only it should be the size of a men’s t-shirt.
Depending on what type of coal is used, it is poured with a layer of 12 to 20 cm. Anthracite, brown and gray coal are suitable for the furnace.
The main thing when burning the furnace with coal is to prevent the penetration of carbon monoxide into the room. To do this, coal is covered with a layer of not more than 20 cm, so that there is enough space for air. Indeed, oxygen for the complete combustion of coal requires more than for firewood. The combustion process must be constantly monitored.
It is necessary to heat the furnace with coal 3-4 times a day. This problem is absent when using factory equipment. There, the design of the boiler is such that one bookmark (without using an additional hopper) is enough for at least 36 hours.
How to make a stove for heating a house with wood and coal?
What to do if buying a factory model is too expensive? Below is a step-by-step instruction on how to make a wood and coal stove yourself.
A schematic diagram of such a boiler can be seen in Fig. Number 3 . For the manufacture of heat-resistant steel with a high content of alloying elements. Sometimes used gas cylinders made of steel grade St3 with a high carbon content.
You can also burn a brick oven with coal. But there are difficulties with constant cleaning. A lot of soot is formed from coal.
A firebox must be made of fireclay bricks. The masonry process itself is also quite laborious and expensive. However, there is a simple option, which is quite suitable for a small country house (up to 36 m2).
For the future you can download the order here.
A step-by-step diagram of the manufacture of a brick furnace on wood and coal:
- For the construction of a furnace, a concrete foundation with reinforcement is required. The dimensions of the foundation must be 100 mm higher than the dimensions of the furnace. And the height is 500 – 700 mm. The top of the foundation is at -0.150.
- Spread the base – the first 2 rows with a standard dressing of vertical seams. The masonry is carried out on a cement-sand mortar. Further, chamotte clay is used as a mineral binder.
- The first row is the bottom of the ash pan. Perform laying clearly according to the scheme.
- When laying 2 and 3 rows, you must not forget to expose and fasten the blower door with wire.
- The fourth row is covered with an ash pan and a hole for the blower.
- The grate is placed in the 5th row.
- The firebox door is installed when laying 6-8 rows.
- Perform masonry according to the scheme. 6 – 9 rows form a firebox.
- 8 row – this is the combustion chamber arch. It is made of ¾ brick. And 9-14 rows overlap it.
- According to the scheme, smoke channels are laid out.
- Gate valves are located in 26 and 29 rows.
- Complete the closure of the furnace.
- Next, lay out the chimney.
- Drying oven.
Even a beginner can make such a furnace with his own hands. It is enough to master the elementary skills of a mason. A sophisticated tool is also not required. Heat-resistant mortar mixes for masonry furnaces are easy to purchase at any construction supermarket.
It is easier and more convenient to purchase a stove. But with a limited budget, you have to make a stove yourself. It is cheaper, but requires certain skills.
The best material for a stove on coal and wood will be heat-resistant alloy steel. However, in practice, old gas cylinders made of St3 steel or brick are more often used. A large cottage cannot be heated with such an oven. But for a country house with 1 – 2 rooms is quite suitable.
How to make such a furnace with your own hands is disassembled above. Of its shortcomings, the need for frequent cleaning should be noted. And such a furnace will have to be heated 3-4 times a day. But coal will warm the room much faster. And such a design will cost 2 to 3 times cheaper than the factory counterpart.
Those for whom the issue of saving is not so acute can buy a factory boiler. Only you need to choose the right power and take into account possible heat loss: window and door openings, etc.
This option has many advantages. One bookmark of fuel is enough for at least 36 hours. Yes, and the unit will have to be cleaned much less frequently. There is only one drawback – you have to spend a considerable amount of money.
How to do it yourself
Coal in terms of efficiency is in second place after gas. Coal stoves are especially popular in regions with expensive imported wood. The heat transfer coefficient of it is higher than that of firewood, therefore, the main fuel in many models of solid fuel boilers is just brown coal or anthracite. Another advantage of coal-fired boilers is the ability to automate the loading and burning process, which is impossible for wood-burning stoves.
Features of coal burning
Firewood is the most ancient type of fuel, and this is explained by the fact that it is easy to obtain and set on fire. Dry wood burns without additional pressurization, while burning takes place in two stages: first, the wood is charred with the release of combustible gases – the so-called pyrolysis, and then the gases themselves burn, forming a flame, the height of which can reach several meters.
Wood-burning stoves and long-burning boilers usually consist of two chambers or zones: in one, the wood decomposes into smoke and ash, in the other burns flue gases and the most intense heating of the walls of the stove occurs. A similar effect is achieved in brick kilns – flame and hot smoke pass through the smoke channels, heating a large area of the brick, while the furnace body heats evenly.
Coal burning occurs differently. The greatest heating is observed on the surface of the fuel, and the temperature of the smoke at the exit is relatively low. Therefore, the effect of prolonged burning of coal furnaces lies in the large load size and placement of the heat exchanger directly in the fuel combustion zone. In brick ovens, the thickness of the walls of the firebox is increased, and the smoke circulation is made less extensive and accessible for cleaning by hand.
Another feature of an efficient coal furnace is the need for forced pressurization of the combustion zone. In furnaces and boilers for industrial production, this problem is solved by installing a blower fan. In a brick kiln, a well-thought-out blower and chimney design is required, providing good traction.
Also, before installing the furnace on coal with your own hands, you need to provide a place to store fuel supplies. Coal is usually bought for one season – it is not recommended to store it longer, since anthracite coalesces. Therefore, you need a separate warehouse, protected from rain and wind.
You also need to consider the installation location of the boiler or furnace. Coal, unlike firewood, dusts and stains household items, and smoke from coal smells unpleasant. Therefore, it is better to place the furnace of the coal furnace in a separate room, and the boiler connected to the water heating system, in general, should be taken out to the boiler room located near the fuel storage.
Industrial coal fired boilers
When choosing a coal-fired home heater, most country house owners stop at long-burning boilers.
They have a whole list of advantages:
- the boiler is installed in a separate room and connected to the water heating system, as a result, the house remains clean and there is no smell of smoke;
- boilers are economical, have high efficiency and good heat dissipation;
- a well-thought-out design provides a small amount of ash; they rarely have to be cleaned;
- the mode of operation at one load in industrial boilers can reach several days, and if you provide a hopper for loading fuel and automatic feeding, then even several weeks;
- expensive boiler models are equipped with automation systems, maintenance is minimized.
We can also note a number of difficulties that arise when buying a coal boiler:
- the need to equip the fuel warehouse and boiler room;
- due to the low temperature of the smoke, condensation and fouling of the chimney with soot are possible, therefore, regular cleaning is necessary;
- high price of industrial boilers and related equipment.
For heating a country house or a cottage with permanent residence, an industrial boiler with process automation is the best choice, despite the difficulties of installing it and the high price. The costs will pay off in several heating seasons, while the operation of the boiler will be safe and economical.
How to choose?
A correctly selected boiler is the key to convenience in service and comfort in the house. In order not to be mistaken, you need to consider all the characteristics of the models you like and read user reviews.
The selection can be made according to the following algorithm:
- Power of the heating unit.
The choice of heating equipment always begins with the selection of power. For an enlarged calculation, it is enough to divide the area of all heated rooms by 10 – the resulting number will mean the estimated boiler power in kW. But this formula is relevant for well-insulated new buildings and the optimal mode of operation of the boiler. In real conditions, it is better to choose a boiler with a power factor of 1.2 to 1.6. That is, for a house with an area of 100 square meters, it is better to choose a boiler with a capacity of 12-16 kW, and for a poorly insulated structure – up to 25 kW. Otherwise, in severe frosts, the temperature in the house can be uncomfortable, and replacing the boiler will cost much more than the initial purchase of a more powerful model.
- Housing and heat exchanger material
Thesecond stage of choosing a boiler is the material from which it is made. Coal heating units are divided into two groups: steel and cast iron.
Advantages of steel boilers for long burning:
o one-piece welded structure, not subject to leakage;
o fast heating and cooling of the walls of the boiler and heat exchanger;
o full automation due to low inertia is possible;
o less weight;
o reasonable price.
Disadvantages of steel models:
- susceptibility to corrosion, especially at welding sites;
- steel boilers cannot be repaired; in case of through corrosion and leaks, the unit is replaced with a new one.
The advantages of cast iron boilers for long burning include:
- resistance of cast iron to corrosion;
- the design of the heat exchanger from separate sections allows partial replacement in case of damage;
- cast iron is a brittle and non-ductile material; in the event of a sharp change in temperature, cracks and fractures are possible;
- higher price than steel models;
- cast-iron boilers are much heavier – 1.5-2.5 times.
- Download Volume and Automation
The frequency of filling the combustion chamber with coal depends on this characteristic. It is worthwhile to analyze whether it will be convenient to engage in coal loading several times a day, or whether it is better to give preference to models with a large loading volume. They occupy a small area, while the loading chamber is quite large, and some models can heat the house on one load for 5 days on anthracite and 3 days on brown coal. Mine boilers are usually equipped with microcontrollers that automate the entire process and minimize maintenance. Boilers with a lower load are usually equipped with a smaller firebox, while they are much cheaper than mine and are easier to handle. Such boilers usually do not have a blower fan, and air intake is due to draft. The chimney for such a boiler should be as simple as possible and have a total length of not more than 5 meters. Advantages of boilers without traction – independence from electricity and low price. Cons – a low level of automation. The least attention and maintenance require a fully automated model with a loading hopper that accommodates a multi-hour fuel rate. Their price, of course, is high, but they have a number of advantages that provide carefree heating during the season:
- a fuel supply mechanism equipped with a tedder;
- built-in and remote sensors that control the combustion process;
- boiling safety valves;
- SMS alarm mode;
- burning function and standby;
- DHW circuit.
Boiler maintenance is reduced to loading the hopper at the beginning of the season and setting the parameters of the required mode.
Choosing and buying a boiler is not an easy task, and given the cost of modern models, it is also costly. Therefore, for small private or country houses, you can evaluate your strength and make a furnace on coal with your own hands.
Can coal be heated?
Many owners of stove-heated houses are wondering: is it possible to use coal instead of firewood in a brick oven? Will it burn as efficiently as in industrial boilers?
The process of burning coal occurs with the release of a large amount of heat, the temperature in the furnace is significantly higher than when burning wood. At the same time, the smoke coming out of the firebox is less hot than with wood burning.
For this reason, a conventional furnace with long smoke channels cannot be heated with coal: smoke entering the pipe will have too low a temperature, which will lead to the formation of condensate and soot. By interacting, they form carbonic acid, which destroys bricks, which ultimately can cause a fire.
In addition, the increased temperature in the furnace can cause its destruction. A firebox for a coal stove made of bricks must be made only of fireclay bricks, and the walls of the stove in this place should be thicker for high-quality heat removal and accumulation.
It is not recommended to burn conventional Russian stove with coal, which has a non-lined firebox and long smoke channels! This will lead to the gradual destruction of the furnace elements!
How to do it yourself?
The design of a brick furnace using coal or briquettes is quite simple, you only need to observe two conditions:
- the furnace must be made of refractory bricks;
- the stove must be equipped with cleanings in all sections of the chimney.
The layout diagram of the universal furnace is shown in the figure. Thanks to a simple device, you can do it yourself, even without experience. The stove has small dimensions, with its help it is possible to heat a country or village house with an area of up to 36 square meters, consisting of one or two rooms. In the latter case, the firebox is placed on the kitchen side, and the back wall, which heats up during the firebox, is taken out into the room.
The furnace consists of a firebox laid out with own hands from refractory fireclay bricks, and a super-heating channel with one undercoat.
In the channel, flue gases are trapped, a bell effect is created, and the furnace body warms up. After cooling, the smoke descends and exits into the chimney through an underfill. It is equipped with two gate valves, eliminating the sharp boundary between warm and cold air and moisture condensation.
Below the firebox there is a blower combined with an ash pan. Supercharging is carried out through the grate, air movement is provided by a simple chimney design and good draft.
- Install the furnace on a stand-alone foundation made of reinforced concrete. The dimensions of the foundation should be 5-10 cm higher than the dimensions of the furnace, its height is 50-70 cm, while it should be 15 cm below the level of the final floor covering. After pouring and drying the foundation, it is leveled with cement mortar, two layers of roofing material or other rolled waterproofing are laid on it, after which they begin laying the furnace with their own hands.
- Two rows are laid out of brick – the base of the furnace, in continuous masonry with red brick dressing. They are placed on a cement mortar.
- Next, the masonry lead in accordance with the scheme for the solution of chamotte clay. The first row forms the bottom of the ash pan.
- In the second and third rows, the blower door is exposed, fixing it with an annealed wire laid between the bricks.
- The fourth row forms the overlap of the ash chamber and the hole for blowing and removing ash from the furnace.
- Starting from the fifth row, the masonry is led by fireclay bricks. In the fifth row they lay the grate.
- In the sixth and seventh, the combustion chamber door is installed similarly to the blower door.
- Rows from 9 to 11 form the walls of the furnace, they are laid with a dressing.
- In the 12th row, the arch is made of ¾ part of the brick, and in 13 and 14 they overlap the arch.
- In the 15th row, a cleaning door and a tuck are installed.
- Starting from the 16th row, the masonry is again made of red brick. According to the scheme, smoke channels are laid out.
- In the 25th and 32th row, valves are installed.
- 33 and 34 rows complete the overlap of the furnace, then lay out the chimney of the desired height.
- The oven is dried in the air, then gently multi-stage, first heated with wood, and after several furnaces with coal. During operation, it is allowed to use any solid fuel: coal, anthracite, firewood and wood waste, pellets and briquettes.
Any metal furnace with the effect of long burning can be adapted for a coal furnace by laying out the lining of fireclay bricks in the furnace with your own hands and equipping it with a fan. With such a refinement, the furnace metal will not burn out from high temperatures, and coal will burn steadily for a long time.
Do-it-yourself brick oven for coal
Household stoves made of brick for coal remain worthy competitors for solid fuel boilers in a situation where it is necessary to heat a small and medium-sized dwelling in winter, and the main gas is not supplied. If in some respects the coal stoves lose to steel and cast-iron heat generators, then in other parameters they have no equal. Therefore, the demand for the construction of brick kilns remains stably high.
The use of coal instead of firewood is an inexpensive and effective option for heating a house.
Benefits of a Brick Heat Source
Putting a solid fuel boiler is easier and cheaper than building a brick heating stove in the middle of the house. On the other hand, for the operation of the unit, it is necessary to mount a water heating system, and the stove can do without it.
Despite the high cost and complexity of construction, many homeowners still prefer brick stoves. The reasons are weighty:
Features of placing the stove in the house.
- Durability. When coal is burned in the firebox of any heater, a rather high temperature occurs, which eventually destroys steel products. While even ordinary ceramic bricks will last for more than a dozen years.
- Cast iron boiler heat exchangers run the risk of cracking due to temperature differences, while the brickwork calmly tolerates the temperature shock.
- Heat capacity. A coal-fired brick stove accumulates a large amount of heat during operation, and the boiler needs a buffer tank for this, which costs a lot of money.
- The masonry gives up the accumulated heat to the room for a long time after the attenuation of coal in the combustion chamber.
- The stove emits healthy, pleasant heat transmitted through infrared radiation and convection.
Since coal stoves still cannot do without firewood required for kindling and heating, an indescribable atmosphere is created in the house, saturated with natural smells of nature. There are 2 varieties of such heat sources:
Properties of fossil fuels
The foundation for a brick oven.
As already mentioned, the combustion temperature of coal is quite high. With sufficient air flow into the firebox, it reaches 1000-1100 ° C, so not every material can withstand such conditions for a long time.
For comparison: dry wood under identical circumstances can produce no more than 700 ° C in a firebox, and even that is very rare. In addition, coal fuel is much more caloric than firewood.
That is, when burning 1 kg of anthracite, almost 2 times more thermal energy is generated than from the same amount of wood.
Previously, in old houses, heating stoves or stoves were laid out only from solid red brick. With constant heating of high-calorie rocks of coal from exposure to high temperature, the masonry began to crumble gradually, so the hosts clad the firebox from the inside with thick steel soles from the railway tracks to protect the walls.
At the moment, the problem of burning coal is solved much easier – using fireclay bricks. The design of the furnace provides for the lining of the fuel chamber with fireclay stone of the ??, ?? or ?? mark to a thickness of a quarter or half brick. This material is able to easily maintain a temperature of 1400 ° C and for a short time – up to 1650 ° C.
Oven masonry tools.
There is another point: because of the higher calorific value than that of a tree, a greater amount of heat is released, part of which goes with the combustion products into the chimney.
To avoid this, a more developed smoke exhaust network is provided in the coal furnace, where the flue gases manage to transfer heat to the brick walls, rather than flying out into the chimney.
The rest is an ordinary brick stove with all the advantages and disadvantages.
How to build a stove?
First you need to understand what are the requirements for a coal heating furnace:
- the heater should warm up evenly and quickly, intensively giving off heat to the indoor air;
- the external walls of the brickwork facing the rooms can be heated up to a maximum of 90 ° C;
- fuel burning should be efficient;
- the stove should be located in the house so that its walls warmed up several rooms;
- when building the body of the furnace and chimney, it is important to comply with all fire safety rules;
- during construction it is not allowed to use combustible materials;
- masonry should be smooth, without cracking;
- the heater should be decorated in accordance with the interior of the home.
When the requirements are known and worked out in relation to your home, you should choose a suitable furnace design and lay a solid foundation for it.
Diagram of the laying of the corner furnace.
A coal stove is a massive and rather heavy construction, and therefore the foundation for it must be made reliable. Its dimensions in the plan are taken 5 cm more in each direction from the dimensions of the future structure.
An important condition: the foundation of a heating or cooking device made of brick should not dock with the base of the building itself, but should be at least 10 cm away from it.
Foundation work is carried out in the following sequence:
- Dig a hole whose depth depends on the location of non-subsiding soil layers (clay). Tamp the bottom of the pit with a manual tamper.
- Pour a layer of crushed stone with a thickness of 10-15 cm and also compact it.
- Further, you can lay the foundation pit with rubble stone with watering with a liquid solution or fill in a reinforced concrete slab. The height of the base is flush with the rough floor.
- For waterproofing, 2 sheets of roofing felt must be laid on the top of the foundation after the concrete has hardened, and for fireproofing, basalt cardboard and roofing steel.
After the foundation is installed, you can proceed to the construction of the stove in accordance with the rules.
For laying the stove, where it is planned to burn coal, you will need 2 types of mortar – clay-sand and refractory. With the help of the first, the furnace body is made of solid ceramic bricks, and the second goes to the internal masonry of fireclay stones. The thickness of the joints is different: for ordinary masonry, it is a maximum of 5 mm, for refractory – 3 mm.
For the preparation of both types of mortar, it is recommended to purchase ready-made building mixtures available on the market. Only experienced stove-makers can make a good solution from natural clay. You also need to prepare a masonry and measuring tool, and then proceed to the construction of the furnace:
- Before laying on the mortar, each row of bricks must be laid out dry to try on and fit the stones in size.
- Before putting the brick in place, it must be dipped in a bucket of water.
- It is advisable to lay stones in one precise motion, so that you have to tap less.
- Cut the remaining solution from the front with a trowel, from the side of the chimney sweeps – wipe it dry with a rag.
- Each row is controlled horizontally and vertically.
- Between normal and fireclay masonry leave a gap of 5 cm wide, which then fill with basalt fiber.
- Install a cast-iron plate with hobs and doors using supporting elements made of rolled metal.
The furnace solution does not harden, but dries, for which it needs to be given for 2-3 days. After that, lay out the chimney, observing the rules for passing through the ceilings and the roof, and at the end make a test firebox. You can fill the furnace with coal only after full heating, making sure that there are no cracks and crevices.
Do-it-yourself making a long burning furnace on coal
The traditional option of burning coal and firewood involves lower combustion of fuel, i.e., by supplying air from below through the grate. The principle of operation of a solid fuel furnace for a long-burning house is radically different – the combustion of fuel occurs from above. The combustion chamber, and the whole body has a round shape. The device is equipped with two doors necessary for laying coal or firewood and for extracting ash. The ash chamber, located below, is divided with the furnace using a grate.
Boilers manufactured in the factory have a special opening necessary for supplying air pumped by the fan to the required temperature. The body of the combustion chamber has a water jacket equipped with fittings for the outlet and entrance of the coolant. The chimney pipe is located on top and is necessary to remove combustion products formed in the upper zone of the furnace.
Ready-made heating boilers have a fan, which is necessary to pump air into the combustion chamber to quickly set the temperature. With the help of automation, the performance and temperature of this structural element are regulated.
A home-made furnace chamber is filled with coal to the lower level of the loading door to prevent loss.
Ignition is made through the same door, and then, by means of a lifting mechanism, a load is lowered onto the fuel, as a result, the door closes. The fan forcing air turns on automatically, the catalyst of which is the temperature of the coolant. After this, the upper combustion of the fuel in the furnace occurs, which is pressured by the load, which drops as it burns, up to the grate.
Disadvantages and advantages
With every year, the popularity of do-it-yourself, long-burning stoves for homes, is growing. This is due to several advantages of these devices on coal:
- The operating time from one bookmark of firewood is twice as long, and coal – three times than that of traditional stoves.
- Simple construction. To make a long-term burning installation with your own hands, you do not need special skills, and the cost will be much lower than that of factory analogues.
- Improving the design as necessary with your own hands.
- The use of almost all types of fuel is coal, firewood, sawdust and other all kinds of waste. The main requirement is the provision of the required amount of air. The moisture content of wood does not play a special role for such a stove.
The experience of craftsmen made it possible to simplify the design, and now you can make a long-burning stove for the home with your own hands at home. The changes affected the method of supplying air to the combustion chamber. The telescopic construction of the factory type is quite difficult to implement and will lead to additional costs. The replacement is a steel pipe whose length exceeds 300-500 mm. the height of the furnace.
At the end of the furnace, a kind of “pancake” and air diffusers are welded. The second end exits the furnace lid and has an air damper necessary to adjust the air supply. Manual adjustment. An air blower is not used. The combustion process and temperature are supported by natural traction.
The disadvantages include the complexity of the implementation of the body of a cylindrical shape . To do this, you need a rolling machine, or at least a pipe bender. As an alternative, craftsmen use old gas cylinders or large diameter pipes. The mass of the structure increases due to the thickness of the walls.
To make a water jacket, it is better to use thin-walled pipes so that the desired water temperature is reached as quickly as possible.
The design feature of the do-it-yourself coal-fired long-burning furnace is the impossibility of loading fuel “on the go”: it is necessary to wait for the previous portion to burn . If during the combustion process the load is raised and the door is opened, smoke will not escape the room. To eliminate this drawback of a coal-fired furnace, it is necessary to install a heat accumulator, which, according to experts, must be included in the boiler harness using solid fuel.
Production – basic recommendations
To use any type of fuel in the furnace, as well as to ensure the maximum service life, it is better to use heat-resistant alloy steel for the manufacture of the combustion chamber. But, in view of the decent cost of this material, you can use a seamless pipe of grade 20, which is used in factories for the passage of medium or low pressure steam. It is worth noting that gas cylinders are made of steel with a high carbon content (St3).
If you decide to make a furnace chamber from an old cylinder with your own hands, it must be borne in mind that its volume will be reduced due to the arrangement of an ash pan and a cut top . Some craftsmen get out of the situation using two cylinders, which can significantly increase the volume of the furnace . Otherwise, the ash pan is not made at all, and the cut off upper part acts as a lid. In the first case there will be difficulties with cleaning, and in the second – such problems are not expected, but this method is suitable only for rooms with a small area. After completing the manufacture of the boiler, the ash pan door must be carefully sealed. It is necessary to maximize the size in accordance with the openings, and trim around the perimeter with a cord of asbestos.
The cost of factory-type long-burning coal-burning furnaces is quite high, and a do-it-yourself design is the only prospect for most homeowners. The duration of the working process, the temperature and the use of any type of fuel eliminate the characteristic disadvantages.
Furnaces for the house on coal of long burning – choose a coal stove
Which charcoal stove to choose for home
A special category of heating equipment is stoves for the home on long-burning coal. Some users mistakenly believe that there is no difference between wood and coal stoves. The error leads to the fact that the furnace starts to work with reduced heat transfer and quickly fails.
Features of the device furnaces on coal
Coal burning is accompanied by increased heat generation. To maintain normal combustion, an increased flow of oxygen into the combustion chamber is required.
The maximum temperature in the furnace, achieved by burning anthracite 2250 ° C (this value is achieved only in blast furnaces, in household equipment, heating is within 1000 ° C), fuel is ignited at 800 ° C.
The combustion features described above affect the design and internal structure of the coal furnace. There are several significant differences between a traditional wood-burning stove and one designed for burning coal:
- The combustion chamber – has a reinforced frame: thickened walls are made of heat-resistant steel or cast iron. The case of a conventional wood-burning stove when burning coal, after a small number of kindling, will simply burn out, since the walls of the furnace are much thinner than that of an analog that works on coal.
- Air supply to the furnace – the principle of operation of the furnace on coal is associated with the need to maintain the intensity of combustion in the furnace chamber. For this, a grate is used and a unique system for regulating the supply and distribution of oxygen in the combustion chamber. Coal-wood stoves have a removable grate. When fired with firewood, they take it out.
- Combustion products – during combustion at a temperature of 1000 ° C, coal is coked. Complete combustion with virtually no residue, observed only at 2250 ° C. Coke settles on the walls of the chimney and combustion chamber. You will need to regularly clean the grate and other parts of the furnace.
The walls of the combustion chamber of a wood-burning stove quickly burn out when burning coal. A few kindling is enough for the stove to become completely unusable.
Which coal is best for a home stove
The standard furnace life is 5-8 years. Several factors affect the life of the product. The right choice of fuel is critical. For this reason, each manufacturer in detail indicates which coal should be used in the operation of the furnace.
The internal structure and features of the combustion chamber are calculated taking into account the specific type of fuel. Any changes are reflected in the thermal characteristics of the heat generator and affect the efficiency of the furnace.
Coal, which is used in home furnaces, is characterized by high heat transfer, low ignition temperature. Most manufacturers of heating furnace equipment give general recommendations regarding the following types of fuel:
- Coal is a general term for several types of fuel with the index A (anthracite), D (long flame), DG (long flame gas). The fuel is optimally suited for the operation of furnace equipment.
For long-burning furnaces, coal of grades D and DG is better. The principle of operation of furnaces is based on the application of the pyrolysis process – the afterburning of exhaust carbon dioxide in the process of burning solid fuel. Grade DG provides a high percentage of the production of combustible gas and is indispensable for modern stove heating with coal.
- Work on brown coal – fuel is distinguished by a high ash sediment content and low calorific value. Not all models of stoves are designed to use this energy source. Some manufacturers categorically prohibit the use of brown coal.
The use of long flame coal is recommended in most of the existing models of furnace equipment.
How to heat a stove in a house with coal
Another difference between a wood stove and a coal stove is the ignition temperature of the fuel. In order for coal to start burning, it is necessary to create a temperature in the combustion chamber close to 800 ° C.
Recommendations for the proper use of the oven indicate the following:
- The kindling is carried out with the help of firewood – first seed is made with the help of arches, small wood chips. After that, stack a portion of firewood sufficient to warm the firebox to the required temperature.
- Layered fuel stacking – long burning furnaces are loaded with small layers of fuel. Firewood and coal are stacked alternately.
First, firewood burns, which creates the necessary temperature for burning coal. After burning the next layer, a small percentage of coking residue and soot is formed. The wood that burns next burns soot, which has a beneficial effect on work and life.
The low consumption of coal in a long-burning furnace makes this type of fuel economically feasible, and the purchase of a heat generator is a completely justified and cost-effective solution.
Which charcoal stove to choose for home
All heating furnaces of long burning on coal for the house, offered by different companies, have a general principle of operation, but differ in some design and thermotechnical characteristics.
When choosing, they are guided by several criteria:
- Type of fuel – there are combined stoves for long burning on wood and coal, and single-fuel models. The first are equipped with removable grates. Models that work exclusively on coal are rare, but they have a long service life. The design uses thickened walls of the combustion chamber.
- The principle of heating the room – air-heated coal stoves for the home, which heat rooms with the help of natural convection of air, are popular. There is a series with an integrated heat exchanger, which has not yet received wide distribution.
- Manufacturer – solid fuel stoves for a long burning house with work on wood and coal are offered by several domestic and foreign brands. Special attention deserves the products of the Russian company Termofor, a series of Professor Butakov. Among foreign brands, KratkiKoza and Dovre are distinguished by good thermal performance.
The Russian company Termofor has released a series of heating furnaces with different power sizes, from 9 to 40 kW. Types of coal heating furnaces offered by the manufacturer:
- Thermofor Student Coal – the heat generator has a capacity of 9 kW and is designed for complete heating of living rooms up to 90 m².
- Thermofor Engineer Coal – furnace equipment with a capacity of 15 kW. There is enough power to heat a residential building with an area of up to 120-150 m².
- Thermofor Professor Coal is the highest-efficiency boiler in the series. Maximum power 40 kW.
- The company Thermofor has created a special heat removal system that allows you to distribute the heat received in neighboring rooms through air ducts.
Rules for installing coal stoves in your home
Reviews of coal-fired furnaces show that consumers make the same mistakes during installation. Violations made during installation affect productivity, thermal performance and safe operation.
Installation work is carried out in compliance with the following recommendations:
- The stove is installed on a non-combustible base. A brick platform is made on the wooden floor, or basalt cardboard is laid, covered with sheet metal on top.
- Long-burning coal-fired gas-fired gas-fired furnaces heat up very much, therefore, according to PPB, fire breaks are left to the nearest walls. The distance to the wooden surface is at least 1 m., To reduce the gap, the wall is insulated with a non-combustible insulation, sheathed on top with a steel sheet.
- As a chimney, a sandwich pipe is used. When passing through floor slabs, a tunnel is installed, filled with basalt thermal insulation or vermiculite. Through the roof, the chimney is carried out through a special cutting.
Furnaces for country and country houses on coal and wood are installed in compliance with the rules described in PPB and SNiP. Strict requirements are imposed on the height of the chimney. The tip of the pipe rises above the roof, depending on the distance from the ridge. A spark arrestor is installed and, if necessary, a traction amplifier is a deflector.
Coal-burning furnaces operate autonomously for up to several days, provide savings (compared with firewood) of up to 15-20%, which explains their popularity among the Russian consumer and their widespread use.
Do-it-yourself long-burning wood-burning stoves
Long-burning solid fuel furnaces are becoming increasingly popular. This is not surprising – ceteris paribus, such a furnace is able to operate on a single load of fuel for a much longer time compared to its conventional counterparts.
At the same time, a long-burning furnace can be heated with firewood, coal, and various wastes of the woodworking industry. An additional advantage of the unit under consideration is the possibility of its independent assembly.
Advantages of a long burning furnace
- High performance.
- Long work on one tab of fuel.
- The availability of automation of the furnace.
- High profitability at excellent operational indicators.
Long-burning furnaces are devoid of almost all the shortcomings of their conventional counterparts. In fact, in such units, the fuel does not burn, but smolders slowly, which allows you to increase the life of the stove on one tab of fuel.
As a result, the owner has much more free time – during operation, the furnace does not require special monitoring and constant monitoring.
Proceed to self-assembly of the long-burning stove. Start by preparing the necessary fixtures.
Set for work
Metal barrel. A 200 liter barrel is best suited. The container should have sufficiently thick walls. Check that the barrel does not show any signs of corrosion or other significant damage. Instead of a barrel, you can use a piece of thick-walled pipe of a suitable size. Also, the furnace body can be made of sheet steel.
Configure yourself in advance that the work on the manufacture of the furnace will be quite dirty and noisy. Therefore, it is best to assemble the oven on the street, in a garage, workshop or other suitable place. Living quarters are definitely not suitable for such work.
Also, make sure that the place of work has the ability to connect to the mains.
Prepare the barrel for making the case. Cut off the top of the container. The Bulgarian will help you with this. Instead of a grinder, you can use autogen or another suitable cutter. Cut carefully and accurately, the cut part will be used in the future.
If there is no barrel, make the case of another material. For example, you can take a piece of large diameter pipe. Weld to it a round bottom made of steel with a thickness of 6 mm or more. If desired, the bottom can be made square – this will allow you to install the stove without welding additional supports.
Weld 4 legs to the bottom of the body. They can be made from scraps of reinforcement, channel or other suitable materials.
Cut a circle from the steel sheet. Its diameter should be slightly less than the diameter of the stove body. In this circle, cut another circle to accommodate the pipe. The optimum pipe diameter is 100 mm.
Weld a piece of pipe to the cut out steel circle. The length of this pipe should be 150-200 mm greater than the height of the boiler body.
Weld on the bottom of the resulting steel “pancake” channel sections. They should be so long that they can be freely placed inside the enclosure. In total, weld 4 segments at an equal distance along the diameter of the steel circle.
In the future, thanks to these channels, the loaded fuel will be pressed down and spent as efficiently as possible.
Make a cover for the stove. At this stage, the tip of the barrel cut off earlier will come in handy. If the furnace is made of pipe or other materials, the lid will have to be made independently from a steel sheet.
In the lid, cut a hole for the pipe that was previously welded to the pancake.
Cut a hole in the barrel to load fuel. Attach the door to the hole. You can do it yourself or buy it in a specialized store. Do not forget to weld the handle to the homemade door.
Below the firebox hole, make another hole of a slightly smaller size and also equip it with a door. Through the bottom hole you can remove the remains of burnt fuel.
With this, your homemade solid fuel stove is almost ready. It remains only to equip the foundation for it and connect the chimney.
Arrangement of the foundation for the installation of the furnace
In the process of burning the furnace, its body will heat up to very high temperatures, so the base for installing the unit should be as resistant to such conditions as possible.
The finished furnace weighs relatively little, so there is no need to deepen the foundation much. However, at the same time, the base must be durable and fireproof.
The order of arrangement of the foundation:
- prepare a small depression;
- lay the bottom of the pit with a brick in one layer;
- pour cement mortar over the brickwork.
Flue pipe installation
Any stove, the principle of which is based on the combustion of any fuel, needs a chimney.
The chimney can be made from an ordinary metal pipe with a diameter of 150 mm. This is the most optimal size. With a larger diameter, the draft will be excessively strong, which will negatively affect the efficiency of the heating unit. With a smaller diameter, the chimney may simply not be able to cope with its task.
First, a small straight piece of pipe is welded to the pre-prepared hole in the barrel body. It is important that its length is greater than the diameter of the unit body.
The main part of the chimney is usually made curved. It is undesirable for the bend to exceed 45 degrees. Try to assemble the chimney with the least number of bends.
At the places where the chimney intersects various kinds of building elements, arrange insulation from refractory materials, for example, from asbestos.
Install a cap on the top edge of the chimney to protect it from debris, snow, and other precipitation.
It is recommended to equip the chimney itself with a valve to regulate the draft level and heating intensity.
Make a collapsible chimney – it will be more convenient to clean it.
In the process, the metal long-burning furnace will be very hot. Therefore, it is better to equip it with a protective screen, especially if the stove is placed in a small room.
If the reflector is made of brick, it will contribute to some increase in the efficiency of the furnace.
The metal cools at about the same speed as it heats up. A brick screen laid around the furnace will accumulate heat during the operation of the heating unit and for some time give off the accumulated energy to the surrounding space even after the furnace has been completed.
Typically, the furnace is lined on three sides, the rear wall is arranged as desired, there is no need to lay out the upper wall.
There will not be much sense in arranging a protective screen if you plan to install the furnace not directly in the heated room, but in a separate boiler room.
How to heat the stove?
For a long-burning furnace, a wide variety of fuels is suitable.
Firstly, it is coal and wood. It is important that the firewood has a low level of humidity.
Secondly, the furnace of such a furnace can be carried out using a variety of waste and products from the woodworking industry. For example, pellets are well suited.
For the manufacture of pellets, you can use almost any organic mass: straw, onion and garlic husks, sawdust, wood chips, cones, nutshells, citrus peels, bark, sunflower husk and many other materials. Pellets are made by dry pressing of raw materials at elevated temperatures.
Important technical details
To make your home-made stove as safe and effective as possible, remember the following simple recommendations and stick to them when carrying out assembly activities:
- during the installation of the chimney (if it will have a prefabricated structure), mount the structural elements so that their connection is made in the opposite direction with respect to the direction of movement of the flue gases;
- in the process of arranging a stove for long burning, be sure to allocate a certain amount of free space around it. The metal tends to expand with increasing temperature and this moment must be taken into account;
- Do not install a long-burning furnace near combustible and flammable objects and any kind of structures that are unstable to high temperatures;
- design the chimney so that it can be disassembled to clean the products of combustion of fuel.
Before you start the furnace in continuous operation, try several different operating modes. As a result, you can choose the best option and use the stove with maximum efficiency and savings.
Have a good work!